The present invention relates to flexible shielded wires such as coaxial cables or a variety of shielded electric wires or cables, which are made flexible by arranging conductive or ferromagnetic metal wires helically overwrapped about the outer circumference of the cable core, adjacent wires being in close contact.
Electric wires or cables of this kind are widely used in electronic devices and, more recently, have been molded into coil shapes. As a result, they are widely used for robots. Thus, it is desirable to have their flexing resistances and shielding capabilities maintained for extended periods of time.
Generally, the shielding layer of a shielded electric wire or cable has heretofore used either a tape of metal foil such as aluminum foil or a braided or closed conductor, as disclosed in Japanese Patent Laid-Open Publication No. 59-215608.
However, such shielded electric wire or cable using metal foil tape or the braided conductor as the shielding layer has certain disadvantages. In a case where it is repeatedly bent, the metal foil or braided conductor can be damaged causing the electric wire or cable not only to lose its shielding capacity but also to possibly short or cut its internal core line. Although the shielded electric wire or cable used as the closed conductor shielding layer initially is too flexible to directly cause the damage or the short, the shielding conductor wires may be offset, as the bending action continues, thereby losing the shielding capability.
In view of the aforementioned defects of the prior art, the present device has an object to provide a flexible shielded cable which is so flexible that it will not lose its shielding capability as it is repeatedly bent.